1. Field of the Invention
A protective boot comprising flexible hollow bellows member configured to operatively house a reciprocating mechanical structure therein to isolate and protect the reciprocating mechanical structure from dust, moisture and other contaminants from the surrounding environment.
2. Description of the Prior Art
Tube like flexible boots have been used in numerous automotive, industrial and other applications to protect extendable or reciprocating members from environmental contaminants. Boots used to protect the junction between telescoping members where there is no relative rotational or pivotal movement between the members, may be fixedly secured at both ends. However, when both ends of a boot are fixedly secured to two elements which rotate with respect to one another, substantial twisting stresses are imposed upon the boot. The compression and expansion of the boot in combination with a twisting motion will fatigue the boot more rapidly. A boot split or torn will expose the protected elements to foreign matter and thus defeat the purpose for which a boot was installed.
U.S. Pat. No. 4,529,213 describes an improved boot structure for protecting the extensible member and the adjacent end of a telescopically reciprocal mechanism from contamination including an elongated convoluted body formed of elastomeric material with an integral band on one end thereof with a special split-ring device. The split-ring device is provided with air passages which allow the boot to breathe as the boot expands and contracts in response to similar movements of the telescopically reciprocal mechanism.
U.S. Pat No. 4,735,596 shows a boot with a bellows interposed between a large diameter ring and a small diameter ring. In the bellows, the crest which is the closest to the small diameter ring is made thinner than the other crests. When the boot is mounted on a mechanical shaft joint, the crest closest to the small diameter ring is folded preferentially, so that the pitches of the other crests are maintained. The other crests are not brought into contact with each other during the cross movement of the mechanical shaft joint or even if they come into contact with each other, the contact pressure reduced, and the durability is thereby enhanced.
U.S. Pat. No. 4,730,834 teaches a mechanical shaft joint boot comprising a bellows having a plurality of crests between a large diameter ring and a small diameter ring in which a crest excluding the first crest between the large diameter ring and the center of the bellows has the maximum top curvature radius. The thicknesses of these crests are made uniform and elongation-compression distortion is restrained from being concentrated at their tops. The widening of the tops of the crests also restrains any kinking phenomenon which may be produced. Therefore, the durability of the tops of these crests is increased and the durability of the boot as a whole is hence also increased.
U.S. Pat No. 3,369,411 describes an elongated longitudinally compressible bellows member including opposite end outwardly projecting neck portions provided with aligned bores opening into the interior of the bellows member. One of the neck portions is adapted to be secured to the neck portion of a pumping T and the other of the neck portions is adapted to be secured to an associated pump rod for reciprocation therewith and each of the neck portions including an annular abutment member secured on its inner end and abuttingly engaged with the remote surfaces of the endmost greater dimensioned sections of the bellows member.
U.S. Pat. No. 4,154,434 shows a flexible boot surrounding a piston rod, sealed at one end to the free end portion of the piston rod and at its other end to the rod end of the associated cylinder. The head end of the cylinder is connected to a source of gas under pressure and the interior of the boot communicates freely with the interior of the cylinder at the rod end thereof. A check valve is provided for relieving the pressure in the boot when it reaches a predetermined value.